#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz=" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = 1e9 + 7;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    ll X;
    cin >> X;
    constexpr ll LEVEL = 100000;
    using P = pair<ll, int>;
    vector<P> lower;
    vector<P> upper;
    ll lower_sum = 0;
    for (int i = 0; i < N; i++) {
        ll v;
        cin >> v;
        lower_sum += ((v >= LEVEL) ? 0 : v);
        ((v >= LEVEL) ? upper : lower).push_back(make_pair(v, i));
    }

    const int upper_size = upper.size();
    const int maximum = 1 << upper_size;
    vector<ll> upper_sum(maximum, 0);
    for (int i = 0; i < maximum; i++) {
        for (int j = 0; j < upper_size; j++) {
            if (i & (1 << j)) {
                upper_sum[i] += upper[j].first;
            }
        }
    }

    const int lower_size = lower.size();
    vector<vector<int>> dp(lower_size + 1, vector<int>(lower_sum + 1, -2));
    dp[0][0] = -1;
    for (int i = 0; i < lower_size; i++) {
        for (int j = 0; j <= lower_sum; j++) {
            if (dp[i][j] != -2) {
                dp[i + 1][j] = -1;
                dp[i + 1][j + lower[i].first] = i;
            }
        }
    }
    for (int i = 0; i < maximum; i++) {
        if (X < upper_sum[i]) {
            break;
        }
        ll rest = X - upper_sum[i];
        if (rest > lower_sum) {
            continue;
        }
        if (dp[lower_size][rest] != -2) {
            vector<bool> use(N, false);
            for (int j = 0; j < upper_size; j++) {
                if (i & (1 << j)) {
                    use[upper[j].second] = true;
                }
            }
            for (int j = lower_size; j >= 1; j--) {
                if (dp[j][rest] != -1) {
                    use[lower[dp[j][rest]].second] = true;
                    rest -= lower[dp[j][rest]].first;
                }
            }
            for (int j = 0; j < N; j++) {
                cout << (use[j] ? 'o' : 'x');
            }
            cout << "\n";
            return 0;
        }
    }
    cout << "No" << endl;

    return 0;
}